public async Task RemoveBook_Test() { var isbn = "1234567890"; var options = TestUtilities.GetOptions(nameof(ThrowBookException_WhenPublishDateIsIncorrect_Test)); using (var actContext = new LibrarySystemContext(options)) { var book = await actContext.Books.AddAsync(new Book { ISBN = isbn }); await actContext.SaveChangesAsync(); } var removeBookDto = new RemoveBookDto { ISBN = isbn }; using (var assertContext = new LibrarySystemContext(options)) { var sut = new BookWebService(assertContext); await sut.RemoveBookAsync(removeBookDto); Assert.AreEqual(0, assertContext.Books.Count()); } }